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Optimal Instructions to Maximize Attack Efficiency in Beginners and Experienced Fencers

Marko Milic, Danica Janicijevic, Aleksandar Nedeljkovic, Ivan Cuk, Milos Mudric, and Amador García-Ramos

This study aimed to determine the instruction that maximizes fencing attack performance and to explore the sensitivity of a novel efficiency index (EI) that considers reaction time, attack velocity, and absolute error to discriminate between beginners and experienced fencers. Instructions that directed attentional focus internally (react as fast as possible and perform the attack movement as fast as possible) or externally (be as accurate as possible) were provided prior to stimulus presentation. The EI did not differ between the instructions in any group (p > .05), the instructions “react as fast as possible” and “be as accurate as possible” promoted in beginners the highest and the lowest EI, and the EI was higher for fencers. Our findings suggest that the EI could be recommended as a general index of fencing attack efficiency.

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Effects of Contextual Interference on Learning of Falling Techniques

Saša Krstulović, Andrea De Giorgio, Óscar DelCastillo Andrés, Emerson Franchini, and Goran Kuvačić

The main aim of this investigation was to determine the effect of high contextual interference (HCI) and low contextual interference (LCI) on motor learning of falling techniques. Thirty-five kinesiology students (21 males and 14 females; mean ± SD, age = 19.4 ± 0.69 years) were randomly assigned to the HCI or LCI practice group. The participants’ task was to learn two judo falling techniques on both sides over 3 weeks. The two-way analysis of variance found no difference between LCI and HCI in the performance at the pretest, posttest, retention, and transfer. Both groups improved posttest and retention performance. Finally, differences were found for both groups between the falling performance in the posttest and the application test (except for the right yoko ukemi fall in the HCI). Lower application test scores led to the conclusion that the 3-week treatment was insufficient to reach the application level of the falling techniques.

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Comparison of an Inertial Measurement Unit System and Baropodometric Platform for Measuring Spatiotemporal Parameters and Walking Speed in Healthy Adults

Luca Correale, Vittoria Carnevale Pellino, Luca Marin, Massimiliano Febbi, and Matteo Vandoni

Spatiotemporal parameters of walking are used to identify gait impairments and provide a tailored therapy program. Baropodometric platforms are not often used for measuring spatiotemporal parameters and walking speed and it is required to determine accuracy. The aim of this study was to compare FreeMed® Platform gait outcomes with a validated inertial measurement unit. There were 40 healthy adults without walking impairments enrolled. Each subject walked along a 15-m walkway at self and slow self-selected speed wearing an inertial measurement unit on the FreeMed® Platform. Stride length and time, right and left stance, swing time, and walking speed were recorded. Walking speed, stride length, and step time showed a very high level of agreement at slow walking speed and a high and moderate level of agreement at normal walking speed. FreeMed® Platform is useful to assess gait outcomes and could improve the exercise prescription.

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Effect of Mental Calculation and Number Comparison on a Manual-Pointing Movement

Joy Khayat, Stéphane Champely, Ahmad Diab, Ahmad Rifai Sarraj, and Patrick Fargier

The present study aimed at examining the effect of mental calculation and number comparison on motor performance measured as the movement time of a fast manual-pointing movement. Three experiments, involving a total number of 65 undergraduate subjects, examined the effect of mental subtraction (complex) and, respectively, of (a) mental addition (simple or complex), (b) mental multiplication (simple or complex), and (c) the comparison of dot sets and number comparison. Each number was written in Arabic. The movement times were analyzed by using a multilevel linear mixed-effect model. The results showed significant improvement of manual-pointing movement performance only after the complex calculations and after number comparison. Possible implication of attentional mechanisms specific to this arithmetical activity is further discussed.

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External Focus in Long Jump Performance: A Systematic Review

Geovani Messias da Silva and Maria Eduarda Crescencio Bezerra

External focus is a way to guide human movement based on outcome rather than execution, therefore all instructions are provided based on factors present in the environment. The aim of this review is to search information about the effects of external focus in the long jump task and to compare its outcomes with other learning methods. For the research, online database search engines such as PubMed, ScienceDirect, Embase, Cinahl, and Scopus were used from January 2010 to June 2020. About 41 articles were identified by searching the online databases, 12 were discarded because they were duplicates, 11 were excluded due to the content of the abstract, and finally, 5 were excluded after evaluating the content of the full text, leaving 13 articles to be included in this review. This review sought to summarize the findings in the literature on the use of external focus in the practice of long jump. The authors concluded that the external focus is a relevant approach and can be used as a tool for the learning process.

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Generalized Finger Motion Classification Model Based on Motor Unit Voting

Xiangyu Liu, Meiyu Zhou, Chenyun Dai, Wei Chen, and Xinming Ye

Surface electromyogram-based finger motion classification has shown its potential for prosthetic control. However, most current finger motion classification models are subject-specific, requiring calibration when applied to new subjects. Generalized subject-nonspecific models are essential for real-world applications. In this study, the authors developed a subject-nonspecific model based on motor unit (MU) voting. A high-density surface electromyogram was first decomposed into individual MUs. The features extracted from each MU were then fed into a random forest classifier to obtain the finger label (primary prediction). The final prediction was selected by voting for all primary predictions provided by the decomposed MUs. Experiments conducted on 14 subjects demonstrated that our method significantly outperformed traditional methods in the context of subject-nonspecific finger motion classification models.

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Effects of Mirror and Metronome Use on Spontaneous Dance Movements

Derrick D. Brown, Jurjen Bosga, and Ruud G.J. Meulenbroek

This study investigated effects of mirror and metronome use on spontaneous upper body movements by 10 preprofessional dancers in a motor task in which maximally diverse upper body movement patterns were targeted. Hand and trunk accelerations were digitally recorded utilizing accelerometers and analyzed using polar frequency distributions of the realized acceleration directions and sample entropy of the acceleration time. Acceleration directions were more variably used by the arms than by the torso, particularly so when participants monitored their performance via a mirror. Metronome use hardly affected the predictability of the acceleration time series. The findings underscore the intrinsic limitations that people experience when being asked to move randomly and reveal moderate effects of visual and acoustic constraints on doing so in dance.

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Individuals With Parkinson’s Disease Retain Spatiotemporal Gait Control With Music and Metronome Cues

Guneet Chawla, Madelon Hoppe, Nina Browner, and Michael D. Lewek

The purpose of this study was to determine the difference in spatiotemporal gait measures induced by stepping to the beat of a metronome and to music cues of various frequencies in individuals with Parkinson’s disease. Twenty-one participants with Parkinson’s disease were instructed to time their steps to a metronome and music cues (at 85%, 100%, and 115% of overground cadence). The authors calculated cadence, cadence accuracy, and step length during each cue condition and an uncued control condition. The music and metronome cues produced comparable results in cadence manipulation, with reduced cadence accuracy noted at slower intended frequencies. Nevertheless, the induced cadence elicited a concomitant alteration in step length. The music and metronome cues produced comparable changes to gait, but suggest that temporal control is more limited at slower frequencies, presumably by the challenge of increasing the step length.

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Interlimb Neuromuscular Responses During Fatiguing, Bilateral, Leg Extension Exercise at a Moderate Versus High Load

Taylor K. Dinyer, Pasquale J. Succi, M. Travis Byrd, Caleb C. Voskuil, Evangeline P. Soucie, and Haley C. Bergstrom

This study determined the load- and limb-dependent neuromuscular responses to fatiguing, bilateral, leg extension exercise performed at a moderate (50% one-repetition maximum [1RM]) and high load (80% 1RM). Twelve subjects completed 1RM testing for the bilateral leg extension, followed by repetitions to failure at 50% and 80% 1RM, on separate days. During all visits, the electromyographic (EMG) and mechanomyographic (MMG), amplitude (AMP) and mean power frequency (MPF) signals were recorded from the vastus lateralis of both limbs. There were no limb-dependent responses for any of the neuromuscular signals and no load-dependent responses for EMG AMP, MMG AMP, or MMG MPF (p = .301–.757), but there were main effects for time that indicated increases in EMG and MMG AMP and decreases in MMG MPF. There was a load-dependent decrease in EMG MPF over time (p = .032) that suggested variability in the mechanism responsible for metabolite accumulation at moderate versus high loads. These findings suggested that common drive from the central nervous system was used to modulate force during bilateral leg extension performed at moderate and high loads.

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The Effects of Texting, Sitting Surface Stability, and Balance Training on Simulated Driving Performance and Perceived Workload in Young and Older Drivers

Faezeh Mohammadi Sanjani, Abbas Bahram, Moslem Bahmani, Mina Arvin, and John van der Kamp

It has been shown that texting degrades driving performance, but the extent to which this is mediated by the driver’s age and postural stability has not been addressed. Hence, the present study examined the effects of texting, sitting surface stability, and balance training in young and older adults’ driving performance. Fifteen young (mean age = 24.3 years) and 13 older (mean age = 62.8 years) participants were tested in a driving simulator with and without texting on a smartphone and while sitting on a stable or unstable surface (i.e., a plastic wobble board), before and after a 30-min sitting balance training. Analyses of variance showed that texting deteriorated driving performance but irrespective of sitting surface stability. Balance training decreased the negative effects of texting on driving, especially in older adults. Perceived workload increased when drivers were texting, and balance training reduced perceived workload. Perceived workload was higher while sitting on the unstable surface, but less so after balance training. Path analyses showed that the effects on driving performance and perceived workload were (indirectly) associated with changes in postural stability (i.e., postural sway). The study confirms that texting threatens safe driving performance by challenging postural stability, especially in older adults. The study also suggests that it is important to further investigate the role balance training can play in reducing these negative effects of texting.